Vulcan Quasar wall furnace, pilot will lit and burner starts but goes out after a few minutes. sometimes pilot will relight but most often fails to light till unit cools down. Any suggestions?

There is a sensor called a pressure switch that is attached to the area of the blower motor for the exhaust fan. It is bad or plugged.

The first thing I would do is make sure the flame sensor is clean, this is a metal rod immersed in the burner flame on the opposite side of the igniter. If too much oxidation builds up on it, it will not allow the burner to stay lit. To clean, just turn off furnace and remove flame sensor and clean with steel wool and then reinstall. If this does not solve the problem there may be a problem with the gas valve.

Hello Lynne,
To relight the pilots,start by removing the floor of the oven,then remove the small access panel below the doors. On the main oven burner will be a small pilot burner that probably looks something like this
on the gas valve behind that small panel under the doors will be a red button,push that red button and hold it in while lighting that pilot burner...continue tohold that red button for 30 seconds,release it and the pilot should be lit.
Good luck,GENE

Simply clean out the jet tube with a fine wire, the sound you hear is the gas blowing by the irregular edges, and swirling and not mixing and producing sound waves, (Bit like a flute) So, you need to clean the tube right out, and smooth off the end again, & sorta "Countersink", Flame the end too, at the end.use a very fine needle file, and make it look like new, that will sort your problem out. Then adjust so you have a good gas flow. Also check out it isn't blocked too.

it sounds like the afc the fan control not working could be dust on the afc

trycleaning the pilot sounds like it too small an dthe heat from the burner is keepinh the thermocople going or try new thermocouple

Have a gasfitter bypass the clock. The clock is the source of the problem. You will then have a manually operated heater.

Look for dust and lint. Look for them in places where gas should be freely flowing. I had a similar problem with an Empire Corcho wall-mounted propane ceramic catalyst heater. First it was the pilot light, then the #2 ceramic mantle. After horsing around with the gas lines and pressure regulators and trying to re-aim the pilot, it all turned out to be dust and lint in the gas passages. A little dust bunny in the brass pilot tube gave me a pilot light the shape and color of a banana. One puff of compressed air, and I got back my razor-sharp pilot. And some dust in the chimney of the #2 burner kept it burning blue/yellow and blistering paint off the upper surfaces of the heater. A bit of cleaning with a shop-vac put that right. "Passive" heaters are very much prone to this sort of problem because they rely on convection currents (i.e. LOW velocity) to get the job done. Convection currents are notorious dust collectors, as in COBWEB CITY.

Relighting Your Furnace's Pilot Light
- Turn off the gas at the main valve at your utility box - Wait five to ten minutes for gas fumes to waft away - Get a long match—yes, a fireplace match, not a standard match - Set the gas valve on your furnace to "pilot" - Press the red button as you hold the match to the pilot valve - Keep pressing the red button for 30-60 seconds so the pilot can heat the thermocouple. Release the button and see if the pilot remains lit - If pilot goes out, wait five to ten minutes and repeat the process - Once the pilot stays lit, turn the main gas valve back on - If the pilot light continues to go out, call a technician, who may need to adjust or replace your thermocouple or adjust your pilot

I would take out the pilot and clean it up and see what happens,also look behind the unit and see if theres a gas regulator on the gas line,if so you will see a nut on it take it off with a pair of pliers and clean as well.that valve is actually the saftey valve,when the pilot lights the flame impinges on the thermocouple and that sends a millivolt back to that valve in order to open.if none of these resolve your problem i would replace the thermocouple first as this is a cheap part and easy to put on.if you need a part # i can give it to you.let me know.